[PATCH 1/5] mtd/spinand: rework detect procedure for different READ_ID operation

[Frieder Schrempf]

On 10.02.23 12:57, Michael Nazzareno Trimarchi wrote:
> Hi
> 
> I will review
> 
> On Thu, Feb 9, 2023 at 5:52 PM Tom Rini <trini at konsulko.com> wrote:
>>
>> On Thu, Feb 09, 2023 at 10:24:47AM +0100, Frieder Schrempf wrote:
>>> Hi,
>>>
>>> On 10.01.23 12:58, Frieder Schrempf wrote:
>>>> From: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
>>>>
>>>> Currently there are 3 different variants of read_id implementation:
>>>> 1. opcode only. Found in GD5FxGQ4xF.
>>>> 2. opcode + 1 addr byte. Found in GD5GxGQ4xA/E
>>>> 3. opcode + 1 dummy byte. Found in other currently supported chips.
>>>>
>>>> Original implementation was for variant 1 and let detect function
>>>> of chips with variant 2 and 3 to ignore the first byte. This isn't
>>>> robust:
>>>>
>>>> 1. For chips of variant 2, if SPI master doesn't keep MOSI low
>>>> during read, chip will get a random id offset, and the entire id
>>>> buffer will shift by that offset, causing detect failure.
>>>>
>>>> 2. For chips of variant 1, if it happens to get a devid that equals
>>>> to manufacture id of variant 2 or 3 chips, it'll get incorrectly
>>>> detected.
>>>>
>>>> This patch reworks detect procedure to address problems above. New
>>>> logic do detection for all variants separatedly, in 1-2-3 order.
>>>> Since all current detect methods do exactly the same id matching
>>>> procedure, unify them into core.c and remove detect method from
>>>> manufacture_ops.
>>>>
>>>> This is a rework of Chuanhong Guo <gch981213 at gmail.com> patch
>>>> submitted to linux kernel
>>>>
>>>> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
>>>> Signed-off-by: Frieder Schrempf <frieder.schrempf at kontron.de>
>>>
>>> +Cc: Jagan, Tom
>>>
>>> Who is supposed to pick up these patches? Some of them have been around
>>> for some months (before I resent them).
>>>
>>> There is no maintainer for drivers/mtd/spinand/ and no maintainer for
>>> drivers/mtd/ in general.
>>>
>>> In Patchwork Jagan got assigned, but the get_maintainer.pl script didn't
>>> even add him to Cc, of course.
>>>
>>> Any ideas how to proceed?
>>
>> We don't have anyone dedicated to that area, yes, sadly. I've added
>> Michael and Dario as they've also been doing mtd-but-not-spi work of
>> late to see if they're interested. Or since you've long been working
>> here, would you like to more formally maintain the area? Thanks!
> 
> They can come from our tree. I will try to sort out all my duties weeked

Thanks Tom and Michael!

I just sent out a patch for the MAINTAINERS file to add Michael and
Dario as SPI NAND maintainers and myself as a reviewer. I hope that you
agree to handle it like this.